The world's largest synagogue sits in scenic splendor atop Sepulveda Pass, a quiet giant strategically positioned between the large Jewish populations on Los Angeles' Westside and in the San Fernando Valley.

Stephen S. Wise Temple, a 18-acre complex at the northern edge of Bel-Air with picture-window views of the Valley, has roughly the same number of families--about 3,000--as the famed Congregation Emmanu-El on Manhattan's 5th Avenue.

But members of the California synagogue have larger families, and an estimated 18,000 people, members and non-members, take part in religious services, support groups and the educational system that includes the nation's only Jewish high school in the liberal Reform tradition.

Indeed, Stephen S. Wise Temple might stand as the pride of Reform Judaism, except for one thing: The synagogue was expelled from the national body in December in a financial dispute.

The conflict stemmed from a disagreement over how much in dues the synagogue should pay to the parent Union of American Hebrew Congregations as it builds a new, $25-million high school campus on the west side of Sepulveda Pass.

News of the controversy became public only in recent weeks, befitting the relatively low-key manner of Rabbi Isaiah Zeldin and a congregation that sometimes has seemed reluctant to seek publicity.

The split with Reform Judaism's New York headquarters will not affect Zeldin's self-sufficient synagogue in terms of rabbinical placement and curriculum services, among benefits of affiliation with the union. But the break comes at an unfortunate time in terms of relations with other Reform synagogues as Zeldin, the founding rabbi, marks some personal milestones.

Zeldin will receive an honorary doctorate Sunday from the neighboring University of Judaism and will be feted May 21 at a Beverly Hills bash honoring his 50 years as a rabbi and his 75th birthday (which is actually July 11).

The $150-a-plate dinner-dance at the Regency Beverly Wilshire is not a retirement party. Aside from a modified rabbinical schedule that includes one Friday service a month and two dozen bar mitzvahs a year, Zeldin says he is very active in projects such as the new high school campus.

"My role model is Edgar Magnin," said Zeldin, referring to the well-known Los Angeles rabbi who led the Wilshire Boulevard Temple for 65 years until his death in 1984 at age 94.

Zeldin didn't mention it, but Magnin pulled the 2,400-family Wilshire Boulevard Temple out of the Union of American Hebrew Congregations in the mid-1970s, although the congregation has since rejoined. Magnin, who was a conservative on many social and political issues, objected to liberal public stances taken by Reform leaders "without consulting the congregations who pay their bills."

Ideological issues are not the problem between Zeldin and the union, said Rabbi Lennard Thal, the Los Angeles-based regional director of the Union of American Hebrew Congregations.

"It boiled down to the level of financial commitment given the fiscal difficulties the temple has encountered in the last few years," Thal said.

Zeldin said the temple has lost about 100 families since 1990, putting current membership at about 2,900 families.

In 1993, the synagogue offered to pay $100,000 a year in dues for the next five years instead of about $200,000 a year, which is what Zeldin said the temple would have owed under the union's assessment system. The system calls for annual payments of 12% of a synagogue's operating budget.

Declining to discuss the union's views on what the synagogue owed, Thal said the union accepts reduced payments under some circumstances but felt the offer was too low. "It was an issue of integrity, and they reached a stalemate," Thal said.

Thal expressed hope that the problem "can be overcome with the passage of a little time."

Zeldin, who was not so optimistic, said in an interview that the assessment system is unfair to large, growing congregations. "A congregation that develops a new program has to add 12% to the cost, because that would be the union's take."

Noting that 200 Reform congregations in October signed a petition asking the national body to lower its fees and re-examine fund-raising strategies, Zeldin said a rebellion is brewing.

"I don't believe the union will survive unless it listens to the voices of objecting congregations," the rabbi said. A proposed dues reduction to 11% will be debated at the union's national convention later this year, Thal said.

But Zeldin said it would be fairer to bill affiliated congregations according to how many members they have, as Christian denominations generally do.

"We would rejoin only if it changes and assesses temples on a per-capita basis," Zeldin said. "Any other method we consider to be wrong."

Zeldin said, however, that he did not know of another Reform congregation in Southern California that is openly opposed to the dues system.